Conventional column-type flight control systems have typically included paired columns for a pilot and copilot. Each column includes handgrips on what can be termed a steering wheel. The columns are pivotable along one axis to control pitch of an aircraft and the steering wheel serves to control roll of the aircraft.
Typically, the two columns are mechanically cross-linked and are connected to parallel mechanical systems (one for port side and one for starboard side) which control the aircraft flight control surfaces. Specifically, each system consists of cables connected by means of pulleys to the aircraft systems (e.g. mechanical, electrical or hydraulic) which in turn control the flight control surfaces in a manner corresponding to movement of the column or the steering wheel thereof. In the event of failure of one of the parallel systems of a corresponding column, the two columns which are mechanically cross-linked can be disconnected by means of a selective connection mechanism.
A disadvantage in these types of systems is that they are often bulky, require significantly more space in an aircraft cockpit and involve addition of servo and trim motors connected to the cable system for autopilot backdrive and trim. Thus, it becomes desirable to replace such systems with active sidesticks, including servomotors, which are smaller and easier to use in controlling an aircraft then conventional column control systems.